Improvement in valve-gear for



UNITED Stai-Es ATENT y Erica.

'rrsDALE oAnrEN'rEE, or rnovinENcE, nnonE isLAND.

Specification forming part of Letters Patent No. 40,3 05, dated December15, `1863.

To all whomit may concern:

Be it known that I, TrsDALE CARPENTER, of the city of Providence, in thecounty of Providence and State of Rhode Island, have invented certainnew and useful Improvements in the Valve Gear of Steam or other Engines;and I do hereby declare that the following is a full, clear, and exactdescription of the same, reference being had to the accompanyingdrawings, forming part of this Specification, in which- Figure l is aplan of the cylinder and valvegear of an engine, showing the val\egearpartly in section. Fig. 2 is a transverse vertical section of the sainein the line :r a; of lig.

l. Fig. 3 is a top view of a' portion of the valve-gear. Fig. 4 is aside view of' the saine.

Similar letters of reference indicate corresponding parts in the severalfigures.

This invention relates more vespecially to valve-gear which ispermanently and positively connected both with the induction or cut-oli'valves of the engine and with a regulator, but which is yet variableunder the control of the regulator to regulate the velocity of theengine by means ofV those valves.

The principal object of the invention is so to connect the regulatorwith thc valve-gear that a slight force only need be exerted by theregulator to materially alter the admission of steam to the cylinder,and by that means make the cut-offsensitive to slight variations inspeed; and to this end it consists in a novel system of right and lefthand screws, racks, and pinions, combined with the regulator and withthe levers or their equivalents, with which the valves are connected,whereby friction-rollers or other devices attached to the said leversare shifted upon the varying face, or between the varying faces, of acam, by which the operation of the valve is produced, and thereby obtainthe necessary variations in the operation of the valves to regulate thevelocity ofthe engine.

To enable others skilled in the art to make and use my invention, I willproceed to dcscribel its construction and operation.

A is the cylinder of the engine, having the induction-valves fitted toits heads B B.

a a are the valve-stems, connected each with one end of one of tworocking levers, C Cf, which work on fixed fulcra b b', secured in agramo, D, which is erected upon the bed-plate E, which supports thewhole of the valve-gear. v

right shaft, G, which at the same time constitutes the spindle of theregulator, and which is driven at the same speed as the crank-shaft ofthe engine by suitable gearing, Il H. The cam F F* is substantially likethat described in the specification of my Letters Patent of Jan-y uary29, 186i, and of myU Reissucd Letters Patent of September 1, 1863-thatis to say, it is composed of two disks, Fand Fit, the opposite faces ofwhichare ot'such varying form as to give the required motion to thevalve by their action upon anti-friction rollers attached to the leverswith which the valves are con` nected, and that such motion may bevaried to keep the valves open for a longer or shorter time by movingthe said rollers nearer to or farther from its center; but to adapt thecam to this improvement its face is modified so that a shorter traverseof the rollers toward and from the center of the cam will produce thenecessary amount of variation in the opening and closing of the valves.

The rollers I I, which Work between the two disks F F* of the cam, arefitted to move longitudinally upon two pins, c c', secured rigidly inthe levers C C, and also turn freely upon the said pins, and they arearranged in line with each other, radial and perpendicular to the axisofthe shaft G,onebeing on one side and the other on the opposite side ofthe said shaft. Each of the said rollers is received in a verticallongitudinal slot, d, provided in one of two parallel horizontal bars, JJ', arranged at right angles to the pins c c', and the pins c c' passthrough transverse slots c e in the said bars, the latter slots beinglong enough vertically to permit the rocking motion of the levers C C.The bars J J are drilled and tapped or fitted with nuts near each endfor the reception of right and left hand screwthreads j" j" on two smallhorizontal shafts, L L, which are arranged parallel with the pins c c inXed bearings g g on the frame D. These shafts are furnished with pinionsh h, gearing with two upright toothed racks, it', which are iitted toslide up and down in guides in the frame D, and which are both connectedwith a crosshead, M, which is tted to slide up and down on the shaft G,and this cross-head is suspended from or connected with the slide of theregulator. Each of the shafts L L has the right-hand screwthread` on oneend and the left-hand screwthread on the other end, and each of the barsJ J receives the right-hand thread of one shaft L and the left-handthread of the other, the arrangement of the right and left hand threadson the two shafts being reversed.

The operation is as follows: rlhe upward and downward movement of thecross-head with any variation in the height of the regulator-slidecauses the racks i i to turn the pinions h h and shafts L L in oppositedirections, and the screw-threads on the latter shafts cause the twobars J J to approach or recede from'the shaft G, and move the rollers 1I upon the pins c c toward or from the center of the cam, according asthe regulatorslide has ascended or descended, and in this Way thenecessary variation in the action of the valves and in the amount ofsteam admitted to the engine is produced. To adjust the valvegear tomake the engine run at different speeds, it is only necessary to raiseor lower the toothed racks relatively to the yoke by means of thescrew-threads on the stems of the racks it and nuts j j, fitted to thesaid threads above and below the yoke.

The particular advantage of this mode of varying the positions of therollers relatively to the center of the cam over that described in myLetters Patent hereinbefore mentioned is that any tendency toward anoutwardthrust by the action of the cams upon the rollers is checked bythe right and left hand screw-threads. Consequently the rise orinclinations on the face ofthe cam may be made much steeper, and thetraverse of the rollers toward and from the center ot' the cam is mademuch less, and consequently the burden upon the regulator is muchreduced, and the gulator allowed to rotate smoothly and Withoutvibration.

One of the screw-shafts L, pinions h, and raekst can be dispensed with,and a single shaft, pinion, and rack be made to effect the same result.'lhe bars J J in such case, being only required to embrace theanti-friction rollers on one side of their pins c c', are made short andfitted to slide along a suitable guide, which both supports them anddirects their motion.

What I claim as my invention, and desire to secure by Letters Patent, is

The employment, in a steam or other engine, of one or more right andlefthand screws,ff', pinions h h, and racks iz', combined with each other,With the regulator, and with theinduction-valve-operating mechanism, andco-operating substantially as described to produce the necessaryvariations in the operation of the valves for the regulation of theengine.

TISDALE CARPENTER.

Witnesses:

HENRY MARTIN, ALBERT M. HEWITT.

